Roller

ABSTRACT

The invention relates to a roller ( 1 ), preferably comprising two wheels ( 2 ) and a locking device, an activating part ( 10 ) acting on the locking device for releasing or locking, and the activating part ( 10 ) being movable by a drive, a movement of a transmission part ( 7 ) that is generated by the drive being transmitted via spring force to the activating part ( 10 ) for moving same, and a spring ( 8 ) being supported on the transmission part. In order to provide a roller that allows an advantageous constructional design, it is proposed that a support region is formed for the spring ( 8 ) and/or the spring ( 9 ) and/or the compression spring ( 44 ) on the activating part ( 10 ), through which region the transmission part ( 7 ) can pass.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the National Stage of PCT/EP2012/060388 filed onJun. 1, 2012, which claims priority under 35 U.S.C. §119 of GermanApplication Nos. 10 2011 051 068.0 filed on Jun. 15, 2011, 10 2011 052693.5 filed on Aug. 12, 2011, and 10 2011 055 418.1 filed on Nov. 16,2011, the disclosures of which are incorporated by reference. Theinternational application under PCT article 21(2) was not published inEnglish.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to a roller, preferably comprising two wheels anda locking device, an activating part acting on the locking device forreleasing or locking, and the activating part being movable by a drive,a linear movement of a transmission part that is effected by said drivebeing transmitted via spring force to the activating part for movingsame, and the spring being supported on the transmission part.

2. The Prior Art

In the case of a known roller, cf. DE 10 2007 039 208 A1, the springsacting on the activating part are supported on the one hand between thetransmission part and the activating part, and on the other hand betweenthe activating part and a housing of the roller. Moreover, it is alsoknown to support both springs on the transmission part.

However, the known construction is relatively large in vertical extent.

SUMMARY OF THE INVENTION

Based on the cited prior art, it is an object of the invention toprovide a roller of the aforementioned type that enables an advantageousconstructional design.

According to a first teaching of the invention, such a roller isprovided with a support region for the spring which is formed on theactivating part, through which region the transmission part can pass.The possibility of nesting the activating part and the transmission partinto one another to a certain degree is achieved in this way. For thispurpose, the activating part can comprise an opening which is open atleast vertically at the top and which allows a corresponding engagementof the transmission part into the activating part and a correspondingmovement of the transmission part relative the activating part. Due tothe fact that the transmission part is provided such that it verticallypasses through to a region for supporting a spring or, as furtherpreferred, in the case of two springs, for supporting both springs onthe activating part, interaction between at least one of the springs andthe transmission part is also enabled in a simple manner below thesupport region for the spring or the springs on the activating part.

The transmission part preferably moves in the direction of compressionor decompression of a spring. With regard to the conventional structureand the conventional arrangement of a roller, the transmission partmoves vertically. More preferably, it moves only vertically, andtherefore not in the sense of a (superimposed) rotational movement, forexample.

According to a further teaching of the invention, it is provided thatthe drive is an electric motor drive, and a component that is comparableto a rotor shaft of a standard electric motor can be provided as a partthat is (only) linearly displaceable. This involves an electric motor,the rotor shaft of which is formed as a hollow part having an internalthread that interacts with a part that has a central external thread andaccordingly is linearly movable when the rotor rotates. Such an electricmotor is also designated as a linear actuator. With regard to linearactuators, reference is also made, for example, to EP 1 555 446 B1 andDE 20 2009 015 840 U1. In the present context, a linear actuator ispreferred in which the linearly moved part (spindle) is centrallydisposed, and a nut (threaded rotor) driving the linearly moved part isdisposed surrounding the latter, within the drive.

The transmission part is vertically movable relative to the support partfor the spring on the activating part. The possibility of nesting theactivating part and the transmission part into one another to a certaindegree is also achieved in this way.

Further features of the invention are described and illustrated below,also in the description of the figures and in the drawings, often intheir preferred association with the features already explained above;however, they may also be of importance in an association with only oneor more individual features which are described herein or illustrated inthe drawings, or independently or in some other overall concept.

In particular, the activating part can have an opening which is open atleast vertically at the top and which allows a corresponding engagementof the transmission part into the activating part and a correspondingmovement of the transmission part relative the activating part. Due tothe fact that the transmission part is provided such that it verticallypasses through to a region for supporting a spring or, as furtherpreferred, in the case of two springs, for supporting both springs onthe activating part, interaction between at least one of the springs andthe transmission part is also enabled in a simple manner below thesupport region for the spring or the springs on the activating part. Thetransmission part preferably passes through the support region only witha linear movement, i.e., without rotation.

The drive can be an electric motor drive, and a component that iscomparable to a rotor shaft of a standard electric motor can be providedas a part that is (only) linearly displaceable. This involves anelectric motor, the rotor shaft of which is formed as a hollow parthaving an internal thread that interacts with a part that has a centralexternal thread and accordingly is linearly movable when the rotorrotates. Such an electric motor is also designated as a linear actuator.With regard to linear actuators, reference is also made, for example, toEP 1 555 446 B1 and DE 20 2009 015 840 U1. In the present context, alinear actuator is preferred in which the linearly moved part (spindle)is centrally disposed, and a nut (threaded rotor) driving the linearlymoved part is disposed surrounding the latter, within the drive.

In the position of the total lock and/or the directional lock, there ispreferably also space for spring deflection, i.e., deflectability, sothat with appropriate manipulation, the activating part can yield in aspring-loaded manner. This is advantageous in particular with regard tothe already described emergency release. This configuration is alsoadvantageous in the case of a positive-fit lock such as a toothed lock,for example. Latching that is not immediately possible at the time ofthe lock release can be compensated for in terms of height. Acorresponding possibility to overrun the position to a certain extent,at least temporarily or initially, is also however important with regardto the drive. In one or both mentioned locking positions, the motor doesnot run “against a block,” and thus, for example, there is no directengagement of spring turns which in this position would have the effectof a solid part. Rather, due to the motor, overrunning this position toa certain extent is possible, which would merely result in a possibleincrease in spring force.

In the case of two springs acting between the transmission part and theactivating part, it is preferred that the springs are arranged one abovethe other. More preferably, the springs abut one another in the verticaldirection, i.e., without forming a vertical overlap region in which bothsprings possibly extend.

It is also preferred that the lower spring is supported by its upper endon the activating part, and the upper spring is supported by its lowerend on the activating part. For this purpose, the activating part canhave a radially inwardly projecting flange, for example, both sides ofwhich serve for supporting one of these springs.

Furthermore, it is also preferred that independently of the operatingstate, which generally can be a full release or a total lock, and morepreferably can also be only a directional lock, the spring, or in thecase of two springs, one of the two springs, is disposed within theactivating part. More preferably, both springs are disposed in each casewithin the activating part, independently of one of the mentionedpositions.

Furthermore, it is also preferred that in the case of one spring, theone spring, otherwise in any case at least one, more preferably bothsprings, is/are disposed outside the transmission part.

It is particularly preferred that the transmission part and theactivating part are formed as geometrically simple bodies, for example,as a rod or a tube. With regard to the formation of the support regionsfor the springs, this merely requires a deviation from the mentionedgeometrically simple configuration.

It is particularly preferred that the transmission part is formed as acylindrical part, with one or both springs being disposed on the outsidewith regard to the outer surface of the cylinder. Preferably, these arecoil springs which are arranged coaxially with respect to the outercylinder surface and surround the transmission part.

In further detail, the transmission part can be formed as a hollow part;on the other hand, however, it can also be substantially formed as asolid part. An internal thread can be provided in the region of itsupper end. The transmission part can be coupled to the linear part ofthe linear actuator by means of the internal thread.

Accordingly, the linear part of the linear actuator can also be a solidpart. At its end facing toward the transmission part, the linear partcan have an external thread which is screwable into the internal threadof the transmission part so as to connect these parts.

The electric motor preferably is a stepper motor, more preferably ahybrid stepper motor or a permanent magnet stepper motor. Specifically,this is also a claw pole stepper motor.

The activating part may have a tubular design. In a deviation from thetubular shape, the mentioned inwardly protruding flange is providedhere, on which flange a spring or the mentioned springs are supported,optionally by means of a washer.

Preferably, the roller also has an emergency release so as to still beable, for example, in the event of a failure of the motor that actuatesthe transmission part, in particular an electric motor, to manuallyrelease a locking position that is occupied, be it a directional lock ora total lock.

For this purpose, the activating part can be moved, in any case in aposition corresponding to the total lock or in any case in a positioncorresponding to the directional lock, relative to the stationarytransmission part into a release position, against a spring supported onthe transmission part, by means of an actuating handle that is movableindependently of the drive and preferably by hand so as to override thetotal lock or the directional lock.

Furthermore, to this end it is preferred that a geometric rotationalaxis of the actuating handle is disposed on the same side as theactivating part with regard to the rotational axis of the wheel, theactivating part being disposed offset, in a vertical section, from therotational axis of the wheel. The actuating handle and the activatingpart are configured to be structurally close to one another. Anadvantageous application of force is thus possible. In particular,advantageous accommodation in the housing is also possible. If, as ispreferred, the activating part is situated in the region of a mountingjournal, if necessary in the vertical extension thereof, the actuatinghandle can also be accommodated in the associated region of the housing.

It is preferred that the geometric axis of rotation of the actuatinghandle runs through the activating part and/or extends in a horizontalplane that passes through a wheel. The fact that the axis of rotationpasses through the activating part means that the actuating handle andthe activating part are to be arranged directly next to one another, thefocus here preferably being on the entire range of movement of theactuating part, including both end positions in the case of adirectional lock or total lock. In this manner, the shortest possibledistance between the actuating handle, which is accessible from theoutside, and the part to be acted on, the activating part, is achieved.Due to the fact that, alternatively or additionally, the axis ofrotation also extends in the horizontal plane passing through a wheel,it is made clear at the same time that the arrangement is providedrelatively far down with regard to the roller.

Furthermore, it is preferred that a horizontal plane which passesthrough the wheel axis also passes through the actuating handle. Thisdescribes the arrangement of the actuating handle at a vertical heightthat corresponds to the center region of a wheel of the roller.

A further preferred configuration provides that the actuating handle isvertically stationary during a movement of the actuating part. Asdescribed below in further detail, in principle it can in first instancebe provided that together with a movement of the actuating part, theactuating handle moves vertically together with the actuating part,which is also possible independently of manual intervention via theactuating handle. However, it is preferred that the actuating handle isstationary so that during a (motor-driven) actuation of the roller, atthe same time no movement of the actuating handle is visible from theoutside. There is, so to speak, a decoupling between the activating partand the actuating handle via a decoupling mechanism which is describedin further detail below. Thus, for example, unintentional blocking ofthe (motor-driven) movement of the activating part due to the actuatinghandle getting externally caught, for example, at a building step or anobject standing in the region of the roller, is prevented.

It is in particular also preferred that a cantilever which interactswith the actuating part interacts with a sliding part guided in thehousing in the direction of movement of the activating part. Thisconfiguration is at the same time also essential for the mentioned,decoupling. Due to the fact that the cantilever moves the sliding part,the sliding part can be disposed inside the roller or inside the housingof the roller so as to be shielded from the outside. It is furtherpreferred in this regard that the sliding part is guided in a stationaryhousing insert through which the actuating handle passes. Thus, thehousing insert is part of the roller housing. The sliding part can alsobe guided directly in a housing shell part. However, with regard to theconstruction, it is more advantageous to provide such a housing insertas an additional feature in the housing.

The actuating handle may have a through pin that acts directly on thesliding part. Since the actuating handle is to be actuated by rotating,such a through pin, which preferably is arranged eccentrically orcomprises an eccentric, can act on the sliding part during rotation ofthe actuating handle, preferably, in particular without undergoing avertical movement at the same time.

It is also preferred that the sliding part has a lower limit stop and anupper limit stop which can be acted on by the through pin for releasingin the total lock or the direction lock. If the activating part is inone of the mentioned positions, the actuating handle having the throughpin is preferably arranged such that there is contact with thecorresponding limit stop of the sliding part, or the limit stop can bereached after a short movement. Then, mechanical coupling between theactuating handle and the sliding part is established so that furthermovement then acts directly on the cantilever, and therefore on theactivating part.

With regard to its rotary movement, the actuating handle can bespring-biased into a neutral position. This neutral position preferablycorresponds to the aforementioned near-engagement position. When theactivating part is in the position corresponding to the total lock orthe directional lock, the through pin, due the neutral position, is incontact or nearly in contact with the corresponding limit stop of thesliding part.

The actuating handle can in first instance be formed such that it can beactuated directly by hand, for example by means of a rib or a projectionformed on the outside thereof. However, it is preferred that it isformed so that it can preferably be actuated only with a simple toolsuch as a coin, a double claw, or the like. Thus, on the one hand, itcan be achieved that handling is always possible in the case of anemergency, and, on the other hand, undesired actuations can also beprevented in the case of a non-emergency.

It is also preferred that an emergency release position, which is set byhand, is latched. The latching can be achieved, for example, in that inthe course of the interaction of the through pin with, one of thementioned limit stops, the through pin moves into a detent recess in oneof the limit stops. However, as can be seen, alternative configurationsfor latching are also possible. Thus, a rotary part of the actuatinghandle itself can interact with a detent cam which, for example, movesinto a circumferential recess. The detent provides for unhinderedmovability of the roller when emergency-released in this manner. Therelease position does not have to be maintained by hand.

It is also preferred that after completion of the emergency release viathe actuating handle, the neutral position of the actuating handle canbe established again by a motor-driven movement of the activating part.This can be achieved in a preferred and particularly advantageous mannerin conjunction with the already-described spring biasing of theactuating handle into a neutral position. Upon releasing the detentposition, the actuating handle then moves back into the mentionedneutral position due to the spring bias. However, it is alternativelyalso possible that after the detent position is released, the actuatinghandle moves, for example due to gravity, into a position in which adetent is no longer provided.

It is also particularly preferred that for re-establishing the neutralposition, the activating part is initially to be moved by motor furtherin the direction of the movement forced by the actuating handle. Oncereleasing the directional lock is achieved due to the actuation of theactuating handle, a further movement of the activating part in thecorresponding direction, which then corresponds to the total lock, takesplace, thereby disengaging the detent position, specifically,disengaging the through pin from a detent recess in one of the mentionedlimit stops, as a result of which the actuating handle is released andcan move into another position again, which no longer results in adetent, or simply into the neutral position. Conversely, in the case ofan emergency release from the total lock, a further movement, which,however, can then only be induced by electric motor, of the activatingpart in the direction of the directional lock is needed to achieve thesame effect. It is further preferred in this regard that in the casethat the activating part is moved by a motor, in particular an electricmotor, this motor always initially passes through a given cycle, so thatin the event that an emergency release has previously taken place, theemergency release is reliably released and the motor is then in thecustomary operating cycle.

With regard to the emergency release by means of a handle, which canthen be actuated independently of the rotary drive, it is furthermorepreferably provided that the activating part is formed with a movementextension, which is furthermore preferably fitted on the outside withregard to the activating part and is movable directly, in particular byhand, so as to move the activating part. It is also possible that whenthe activating part is moved, for example by the mentioned rotary drive,the handle for the emergency release also undergoes a movement,optionally even in a visible manner, preferably in the verticaldirection. However, if an emergency release is to be carried out, therequired movement of the activating part can be carried out manually bymeans of the handle.

The handle can in particular also be formed as a rotary lever. By meansof interaction with a support which is fixed to the housing, the rotarylever can transmit a displacement force vertically upwardly orvertically downwardly onto the activating part. For this, a cantileverfixedly connected to the activating part and serving as movementextension can be provided between the activating part and the rotarylever. The rotary lever is preferably fitted to the outside of thehousing. Upon actuating the transmission part or the activating part, itcan be seen that the rotary lever moves vertically upwardly orvertically downwardly, but by doing so does not undergo a rotationalmovement, but, rather, only the mentioned vertical movement.

It is further preferred that the spring can be lifted off the supportregion on the activating part by means of the transmission part. Acorresponding carrier is preferably formed on the transmission part, andlifts the spring off the activating part during a corresponding movementof the transmission part relative to the activating part.

Furthermore, the activating part preferably forms a lower centralchamber which is open at the bottom and in which one of the springs orthe spring is accommodated. In this respect, the activating part has abell-like design. The central chamber, which is open at the bottom, ispreferably also a cylindrical chamber.

With regard to the mentioned lifting of the spring off the supportregion, an upward lifting is preferably possible; it is furtherpreferred, however, that locking via a corresponding limit stop, forexample via an inwardly protruding step on the activating part, ispossible at the bottom. When the spring is vertically moved further downrelative to the activating part, it cannot be moved beyond a positiondefined in this respect.

Furthermore, an upper support region for the spring is preferably formedon the transmission part. With regard to this support region, it ispreferably also provided that the spring can be lifted off in thedownward direction. Accordingly, comparable to the mentioned support onthe mentioned activating part, when the spring is moved upwardlyrelative to the transmission part, it cannot be moved beyond the supportregion.

With regard to the handle, which, if necessary, can be used for carryingout the emergency release, it is also preferred that the handle movestogether with the activating part. When various customary operatingstates such as a directional lock and/or a neutral position and/or atotal lock are assumed, a change between these operating positions isvisible from the outside in the form of a corresponding displacement ofthe handle in the vertical direction.

In other respects, the handle is preferably fixedly connected to theactivating part, with the exception that it is rotatable relative to theactivating part. Furthermore, one or two abutments associated with thehandle is or are formed on the housing, preferably on the outsidethereof. The handle is movable relative to a stationary abutment. Forexample, by rotating the handle, supporting on an abutment can takeplace, and the supporting movement toward the activating part cantherefore be used for moving the activating part from the total lock orthe directional lock into the neutral position.

Furthermore, such a movement of the activating part by means of thehandle is preferably carried out relative to the stationary transmissionpart while carrying along the supporting region or the support region ofthe spring. With regard to the support region, there can also be anupper support region on the activating part via which the spring iscarried along during a corresponding movement of the activating part.This relates in particular to the movement of the activating part fromthe directional lock into the neutral position.

If two springs are provided, it is preferred that one spring is requiredfor moving the activating part into a position corresponding to thetotal lock, and one spring is required for moving the activating partinto a position corresponding to the directional lock. The functions ofthe springs can be separated in this manner.

In the case of two springs, which are preferably also arrangedvertically one above the other, the lower spring can be supported withits [upper] end on the activating part, and the upper spring can besupported with its lower end on the activating part.

Also, it can be provided that a spring and/or the first spring and/orthe second spring is/are disposed within the activating part.Preferably, a plurality of springs is in each case disposed completelywithin the activating part, in any case in a position that correspondsto the neutral position. However, a position that corresponds to thedirectional lock and/or a position that corresponds to the total lockis/are also preferred. This can be achieved by an overall tubular designof the activating part in which a spring or, if applicable, two springsare arranged in particular vertically one above the other. This can alsobe achieved only in the lower portion of the activating part, forexample by means of the mentioned bell-shaped widening. Furthermore, itis also preferred that a spring or, if two springs are provided, atleast one of the two springs or both springs is/are disposed outside thetransmission part. The transmission part can thus be formed in a verysimple manner even in this region, in any case as a solid part.

It is further preferred that the transmission part is disposed withinthe activating part. It can thus also be guided in an advantageousmanner within the activating part. Guiding the transmission part withinthe activating part can also be achieved, for example, by means of asupport part and/or supporting part.

With regard to the handle, it is preferred that the handle is rotatablerelative to the carrier or the movement extension.

With regard to the respective end positions of the linear part and/or ofthe transmission part and/or of the activating part, it is preferredthat they are monitored by sensors, more preferably by sensors arrangedoutside the electric motor. The respective end positions can be takeninto account in a controller of the electric motor. However, if an endposition is not reached, or is not reached after a given period of time,a warning message can also be output, for example.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in greater detail below with reference to theaccompanying drawings, which show exemplary embodiments of theinvention. A part that is explained only with reference to one of theexemplary embodiments, and in a further exemplary embodiment is not(specifically) replaced by another part due to the special featureemphasized therein, is therefore also described for this furtherexemplary embodiment as a part which in any case is potentially present.In the figures:

FIG. 1 shows a perspective view of a roller implemented as a doubleroller;

FIG. 2 shows a rear view of the roller according to FIG. 1;

FIG. 3 shows a cross-section through the roller according to FIG. 1 andFIG. 2, sectioned along the line III-III in FIG. 2;

FIG. 4 shows an illustration according to FIG. 2 in the state of thedirectional lock;

FIG. 5 shows a cross-section through the object according to FIG. 4,sectioned along the line V-V;

FIG. 6 shows an illustration according to FIG. 2 in the state of thetotal lock;

FIG. 7 shows a cross-section through the object according to FIG. 6,sectioned along the line VII-VII in FIG. 6;

FIG. 8 shows an illustration of the roller according to FIG. 1 and FIG.2, 4 or 6, after completion of the emergency release;

FIG. 9 shows a cross-section through the object according to FIG. 8,sectioned along the plane IX-IX, after an emergency release from theposition according to FIG. 5;

FIG. 9a shows an illustration according to FIG. 9, after an emergencyrelease from the position of FIG. 7;

FIG. 10 shows a perspective cross-sectional view of the roller accordingto FIGS. 1 to 3;

FIG. 11 shows an exploded view of the activating part in the region ofthe emergency release;

FIG. 12 shows a perspective view diagonally from below of the partsinteracting with regard to the directional lock and the total lock;

FIG. 13 shows a perspective illustration corresponding to FIG. 1 of afurther embodiment;

FIG. 14 shows a rear view of the roller according to FIG. 13 in theneutral position;

FIG. 15 shows a cross-section through the roller according to FIG. 13and FIG. 14, sectioned in the plane XV-XV in FIG. 14;

FIG. 16 shows an illustration of the roller according to FIG. 14 in aposition corresponding to the directional lock;

FIG. 17 shows a cross-section through the roller according to FIG. 16,sectioned in the plane XVII-XVII in FIG. 16;

FIG. 18 shows an enlarged detail of the region XVIII in FIG. 17;

FIG. 19 shows a perspective illustration of a detail of the partsinteracting with regard to the directional lock;

FIG. 20 shows an illustration of the roller according to FIG. 14 in aposition corresponding to the total lock;

FIG. 21 shows a cross-section through the roller according to FIG. 20,sectioned in the plane XXI-XXI in FIG. 20;

FIG. 22 shows an illustration of the roller according to FIG. 14 aftercompletion of the emergency release;

FIG. 23 shows a cross-section through the roller according to FIG. 22,sectioned in the plane XXIII-XXIII, after an emergency release from theposition in FIG. 17;

FIG. 23a shows a cross-section corresponding to FIG. 23, aftercompletion of the emergency release from the position in FIG. 21;

FIG. 24 shows a perspective cut-away illustration of the embodiment inFIGS. 13 and 14 in the position according to FIG. 14;

FIG. 25 shows a perspective illustration of a roller in a furtherembodiment;

FIG. 26 shows a rear view of the roller according to FIG. 25;

FIG. 27 shows a rear view according to FIG. 26 in a positioncorresponding to an emergency release from the directional lock or thetotal lock;

FIG. 28 shows a cross-sectional illustration of the roller according toFIGS. 25 to 27, in the neutral position;

FIG. 29 shows an illustration according to FIG. 28 in the directionallock;

FIG. 30 shows an illustration according to FIG. 28 in the total lock;

FIG. 31 shows an exploded illustration of the parts interacting for theemergency release;

FIG. 32 shows an enlarged detail according to the detail XXXII in FIG.29, but after completion of an emergency release; and

FIG. 33 shows an illustration according to the detail XXXII in FIG. 29,but after completion of an emergency release and

FIG. 34 shows an illustration according to FIG. 24 of the embodimentaccording to FIG. 28.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring in first instance in particular to FIGS. 1 to 12, a roller 1formed as a double roller is described. The roller 1 has two wheels 2and a mounting journal 3. As will be explained in greater detail below,an electric motor 4 is disposed in the mounting journal 3, the powerconnection 5 of the electric motor being led, preferably centrally, outof the top of the mounting journal 3. The electric motor 4 effects alinear drive movement of a linear part 6 (see FIG. 3) that acts on atransmission part 7 for vertical adjustment.

The transmission part 7 interacts with an activating part 10 viacompression springs 8, 9.

As further shown in FIG. 1, a handle 11 for emergency release of theroller 1 is fitted to the housing of the roller 1, optionally on themounting journal 3 or in extension thereof or, in the exemplaryembodiment, in the lower region thereof. Above and below the handle 11,which is specifically formed as a rotary lever, abutments 12, 13 areformed on the housing.

In FIG. 2 and also in FIG. 14, a rear view of the roller according toFIG. 1 is represented in a neutral position. In this position, there isno directional lock and no total lock. The roller can rotate freely andthe wheels can roll freely.

Further referring to FIG. 3 and also, for example, to FIG. 15, it can beseen that the wheels 2 are disposed on an axle 14. The sectional viewshows a central housing part 15 that is formed between the wheels 2.

The housing part 15 is arranged by means of antifriction bearings 16 tobe rotatable relative to the mounting journal 3, which is stationary inthe assembled state. The wheels 2 further comprise an internal toothing17 provided for rotational locking. In interaction with an engagementpart 18, for example, one engagement part per wheel, but also, ifnecessary, with two engagement parts per wheel (cf. second embodiment),the internal toothing 17 forms a first part of the locking device in theexemplary embodiment. The engagement part 18 is biased into the releaseposition according to FIG. 3 by a leg spring 19. The leg spring 19 issupported on the one hand on the engagement part 18 and on the otherhand on an inner region of the housing part 15, namely on the bottompart 20 thereof, which in the exemplary embodiment is formed as a partof the housing part 15.

Furthermore, the engagement part 18 is held via an axle 21 so as to berotatable in the housing 15 or the bottom part 20. The axle 21 isformed, in a pivot part 43 which has two bearing receptacles 23 for theaxle 21 and a further axle 22. The axle 22 supports the engagement part18 on the leg part 42. An acting portion 24 is fixedly connected to thepart that accommodates the bearing receptacle 23 and the axle 21. As isapparent, for example, from the illustration according to FIG. 10, theacting portion 24 is centered in the direction toward the axle 14between two lateral acting portions 25. Each of the lateral acting parts25 acts directly on one of the two engagement parts 18 associated witheach wheel 2.

Except for the difference of two springs versus one spring, inparticular the above-described designs of the two embodiments correspondto one another.

The activating part 10 is at least substantially tubular. Furthermore,the activating part 10 has a support flange 26 on the inside whichserves as a support region, and on which, in the first embodiment, thecompression spring 8 and also the compression spring 9 are supported. Inthe exemplary embodiment, supporting occurs by means of a washer 27.

The two springs 8, 9 provided in the first embodiment are arranged oneabove the other.

The lower spring 9 is supported by its upper end, and the upper spring 8is supported by its lower end, on the activating part 10 by means of thesupport flange 26. The arrangement of the springs one above the other isprovided without vertical overlap.

The upper spring 8 is used for moving the activating part 10 into theposition corresponding to the total lock (see FIG. 7), and the lowerspring 9 is used for moving the activating part 10 into the positioncorresponding to the directional lock (see FIG. 5).

The transmission part 7 extends within and coaxially with respect to theactivating part 10. In both embodiments, the transmission part 7 issubstantially solid, the transmission part having an internal threadassociated with the upper end 28 thereof. The internal thread interactswith the external thread of the linear part 6. By a rotational movementof the rotor of the electric motor 4, which rotor is preferably formedhere corresponding to a nut having an internal thread, the linear part 6and therefore the transmission part 7 can thus be moved upwardly ordownwardly. Therefore, the transmission part 7 is also moved up and downpreferably only linearly, thus, without rotating.

On the underside, the transmission part 7 has a head 29 that is formedcorresponding to a screw head. The head 29 can also be used tosupplement the guidance within the activating part 10. A further guidingeffect is provided by the inner surface of the support flange 26,through which the transmission part 7 passes axially in a freely movablemanner.

On the upper side of the head 29, a further washer is arranged which,with regard to the second embodiment, is also designated as a supportpart 48, and on which the underside of the compression spring 9 issupported.

As can be seen, the support of the spring 8 on the activating part 10and/or the support of the spring 9 on the activating part 10 and/or thesupport of the compression spring 44, whether in the lower or upperregion, on the activating part 10 can in each case be passed through bythe transmission part 7.

Furthermore, the activating part 10 is fixedly connected, in any case inthe vertical direction, to a movement extension formed as a cantilever30. The cantilever 30 can, for example, also be welded to the activatingpart 10. In the exemplary embodiment, formations 31 for directionallocking are formed on the upper side on the cantilever 30 (see FIGS. 10and 11), and on the underside (see FIG. 12) projections 32 are formedfor directional locking in the case of the total lock. The arrangementof the cantilever 30 (in this respect, both embodiments are inaccordance with one another) is provided with vertical spacing from thelower and/or upper end of the activating part 10. Furthermore, thearrangement of the cantilever 30 is preferably provided to be eccentricwith regard to the vertical height of the activating part 10, namely,preferably closer to the lower end of the activating part 10. Thespacing of the cantilever 30 from the lower end of the activating part10 once again preferably corresponds approximately to a range of one tothree times the (outer) diameter of the activating part 10, and, ifapplicable, in the case of a difference, with regard to the lower regionthereof.

Due to its fixed connection to the activating part 10, the cantilever 30moves together with the activating part in the vertical direction.

Furthermore, the handle 11 is connected to the cantilever 30, inparticular by means of a sliding part 33 in the first embodiment. Thesliding part 33 is accommodated so that it is movable only in thevertical direction in guides 34 that are fixed on the housing and act inparticular in the lateral direction.

In the exemplary embodiment, the sliding part 33 is connected to thecantilever 30 by a positive locking connection 35. The connection is inany case established in such a manner that a movement of the slidingpart 33 in the vertical direction is transmitted directly to thecantilever 30, and therefore to the activating part 10.

The handle 11, which is arranged to be rotatable relative to the slidingpart 33 or, where applicable, is arranged directly on the sliding partso as to be rotatable relative thereto, can be used for the emergencyrelease if, for example, the electric motor 4 cannot be actuated, asexplained hereinafter in greater detail.

The roller 1 can be operated as follows:

Starting from the position according to FIGS. 1 to 3, the linear part 6can be moved by means of the electric motor 4 in such a manner that avertical movement of the transmission part 7 takes place; compare thedifference in the position of the transmission part 7 in FIG. 3 and inFIG. 5. Since there is a tendency toward a reduction in the spacingbetween the head 29 of the transmission part 7 and the support flange 26of the activating part 10, a force is hereby exerted on the activatingpart 10 via the spring 9, which force moves the activating partvertically upwardly. The cantilever part 30, which is fixedly connectedto the activating part 10, thus likewise moves vertically upwardly andinteracts with a directional locking part 36 that is fixedly mounted onthe housing. In the directional locking part 36, formations [sic;recesses] 37 are formed in which the formations 31 (decent recesses)engage upon corresponding alignment of the wheels 2 of the roller 1, sothat the directional lock is achieved with regard to a selecteddirection.

A linear movement of the linear part 6 of the electric motor 4 in theopposite direction causes a downward displacement of the transmissionpart 7, thus from the position in FIG. 3 or FIG. 5 into the positionaccording to FIG. 7. The spring 8 causes a downward movement of theactivating part 10, the spring being axially fixedly supported on thetransmission part 7 by the disc 38, which, with regard to the secondembodiment, is also designated as support part 45, and the retainingelement 43 as abutment. A front end 41 of the activating part 10 thusacts on the acting part 24, thereby moving the engagement part 18against the action of the leg spring 19 into the engagement positionaccording to FIG. 7.

At the same time, the cantilever part 30 moves downwardly together withthe activating part 10. The projections 32 formed on the underside ofthe cantilever engage with the holding recesses 39 (projections) of thelocking part 40, and thus effect the directional lock. As can be seen,one direction, which is then locked, can be provided out of amultiplicity of different directions. In contrast, in the case of thesingle rotational lock (see in particular FIG. 5 and the relateddescription), it can be provided to lock (in each case) only onedirection. However, as an alternative, as described, for example, forthe second embodiment, it is also possible to lock only one directionfrom a multiplicity of directions.

The locking part 40 is fixedly mounted on the housing.

With regard to the fact that it is necessary to provide for thepossibility that the electric motor 4 cannot be actuated, for examplebecause of a power outage, precaution is taken that the directional lockor the total lock can be released by hand.

This merely requires rotating the handle 11, which is disposed on thesliding part 33 so as to be rotatable relative thereto. If, as a resultof the directional lock, the handle 11 is in the position according toFIG. 4, by rotating it counterclockwise, the handle can be supported onthe abutment 12 that has a corresponding supporting surface thatpreferably is not arc-shaped, whereby, without changing the position ofthe transmission part 7, the activating part 10 is moved verticallydownwardly, thereby compressing the spring 9.

If the roller 1 is in the total lock according to FIG. 6, the handle 11,by rotary actuation in counterclockwise direction, can be supported inthe same manner on an abutment, now the lower abutment 13, so that theactivating part 10 is moved upwardly against the action of the spring 8without changing the position of the transmission part 7. The positionafter an emergency release from the total lock is illustrated in FIG. 9a. The handle position corresponding to an emergency release can belatched.

The position of the activating part 10 and of the transmission part 7,which does not move during any emergency release, is shown in FIGS. 9and 9 a.

With regard to its rotatability, the handle 11 can be spring-biased intoits neutral position according to FIG. 1.

In order to bring the handle back into its initial position, manualactuation of the handle into its neutral position is required.

The further embodiment is described with reference in particular toFIGS. 13 to 24.

A significant difference from the previously described embodiment isthat only one spring is provided between the transmission part 7 and theactivating part 10, namely, the compression spring 44.

With regard to support, the compression spring 44 can be alternatinglysupported on the transmission part 7 or the activating part 10.

In the upper region, the compression spring is supported in firstinstance an the transmission part 7 itself by means of a support part45. For this purpose, in particular a counter limit stop 46 for thesupport part 45 is formed on the transmission part. Furthermore, thecounter limit stop 46 is preferably achieved by tapering the shankdiameter of the transmission part 7. The shoulder which is thus formedforms the counter limit stop for the support part 45 in the upwarddirection.

However, when the transmission part 7, starting from the position inFIG. 15, moves further upwardly, for example into the position in FIG.17, the support part 45 cannot follow the counter limit stop 46 on thetransmission part 7, and instead remains on or reaches the support onthe activating part 10. In particular, a counter limit stop 47 is formedfor this purpose on the activating part 10, which counter limit stop isin particular achieved by a step resulting from an increase of the clearinside dimension of the activating part 10.

In this respect, during a movement of the transmission part 7 from aposition corresponding to the neutral position into the directionallock, a change in the support of the compression spring 44 takes place,namely, from the support on the transmission part 7 to the support onthe activating part 10. The support part 45 switches from a support onthe counter limit stop 46 to a support on the counter limit stop 47. Atthe same time, if it has not already taken place previously, acorresponding change can also take place in the lower region of thecompression spring 44. The support part 48 and therefore the compressionspring 44 are in any case no longer supported on the limit stop 50, butrather, only on the head 29 and therefore on the transmission part 7itself.

The support part 48, the same as the support part 45, is displaceablerelative to the transmission part 7, in any case in the region of theshank portion 49 that has a thinner diameter.

Furthermore, here as well, a limit stop is formed on the underside ofthe activating part 10, which limit stop cannot be overrun by thesupport part 48. This is the limit stop 50, which can be formed, forexample, by a circlip that is inserted at this location in an innergroove of the transmission part 10. In this respect, here as well asupport region is formed through which the transmission part 7 can passthrough—in this case, in the downward direction.

In addition, an overlap on the front end engages over the support part48 by means of the head 29 of the transmission part 7, which has alreadybeen discussed and also described in connection with the firstembodiment. Thus, the support part 48 cannot run over a front end of thetransmission part 7.

If, again approximately corresponding to FIG. 17, the transmission part7 is now moved upwardly from the position in FIG. 15, the support part48 is carried along accordingly. Thus, the compression spring 44 isshortened and its compressive force is increased, unless, as intended infirst instance, the activating part 10 is moved upwardly as a result ofthe spring force. This upward movement by means of the spring forceoccurs via the support part 45 and the counter limit stop 47 on theactivating part 10.

Referring to FIGS. 18 and 19, the structure and the interaction betweenthe parts for achieving the directional lock are further explained.

Also in accordance with the embodiment described in first instance, acantilever 30, which in this embodiment has engagement holes 51, isconnected to the activating part 10. Accordingly, the directionallocking can take place from a plurality of possible directions. In thisembodiment as well, the cantilever 30 is enclosed on one side by apositive locking part 35 on which the handle 11 is mounted outside thehousing 15. In the region of a narrowing (preferably cylindrical) outerdiameter of the activating part 10, the cantilever 30 is connectedfixedly, in any case with regard to a vertical movement, to theactivating part 10. As can be seen, the cantilever is already connectedat the top by the step 52 formed due to the narrowing. Furthermore, withregard to a downward movement, the cantilever can also be connected, forexample, by a shrink-fit connection, or welding. or any other fixedconnection.

In this embodiment, the directional lock 36 which is fixedly mounted onthe housing is provided with downwardly facing engagement projections53. Accordingly, the engagement projections engage in the engagementholes 51 of the cantilever 30 when they move toward one another.

The same as in the first embodiment, as a result of the directionallock, the housing 15, which due to the antifriction bearings 16 is inprinciple rotatable relative to the mounting journal 3 and therefore inparticular relative to the activating part 10, is rotationally locked tothe activating part 10.

With regard to a total lock, corresponding engagement projections 54 arealso formed on the underside of the cantilever 30, corresponding to aposition of the total lock of the activating part 10. As can be seen,these engagement projections can preferably be formed as one piece withthe corresponding housing part.

As is apparent in particular from FIG. 19, the cantilever 30, whichpreferably is disc-like, can have an inner contour that deviates fromcircularity. Flat portions 55 can be provided, which preferably face oneanother. The flat portions 55 can interact with corresponding flatportions on the outer contour of the transmission part 10, which is notillustrated in detail.

In this embodiment as well, the positive locking part 35 is accommodatedin a guide 34 of the housing, thereby forming a sliding part 33. Thepositive locking part is thus movable relative to the housing. In doingso, it correspondingly carries along the rotatably connected handle 11vertically, which handle, however, is otherwise fixedly connected to thesliding part or the cantilever 30.

Furthermore, for a total lock, the activating part 10 acts on theoverall four engagement parts 18 provided in the second embodiment.

The engagement parts 18 are each formed on lever parts 56 and 57,respectively, which are fixedly mounted in the housing via axles 58, 59.The corresponding housing part 60, which, as can be seen here, is alsoreinforced in a grid-like manner, is stationary, while the internaltoothing 17 correspondingly revolves together with the wheel.

The two lever parts 56, 57 are connected via a pivot joint 61 at theirmutually facing ends. A corresponding pivot joint axle 62 can movesubstantially in the radial direction in an elongated hole 63.

Furthermore, the lever parts 56, 57 are biased into their non-engagementposition by a clip spring 64, as illustrated, for example, in FIG. 23.

In the second embodiment, the action by the activating part 10 takesplace in particular by means of a clip part 68, which can also have aresilient design.

As is further shown, in a side view the clip part 68 is substantiallyU-shaped, comprising two U legs 64, 66 and a pivot axis 67. As isapparent, for example, from FIG. 24, the lower U leg 66 shown in theillustration is provided twofold, with the two legs being horizontallyspaced apart, which in each case act on an associated head surface of anengagement part 18 associated with each of the wheels.

With regard to the first embodiment but in particular also with regardto the second embodiment, the design of the engagement parts 18 is alsoof importance, independently of the actual design of the activating part10 and/or the interaction of this actuating part 10 with thetransmission part 7.

Thus, provided with regard to the second embodiment are in particularthe formation of each of the engagement parts as levers, which areconnected in an articulated manner at associated ends, and/or the actionon only one of the two engagement parts associated with the respectivewheel so as to bring both engagement parts into the engagement position,and/or the action on the engagement parts by a clip part, and/or thefurther details that are described above in this regard.

The roller 1 according to the second embodiment is operated basically inthe same manner as the roller 1 of the first embodiment.

Starting from the position according to FIGS. 13 to 15, the linear part6 is moved by means of the electric motor 4 in such a manner that withregard to a total lock, a vertical downward movement of the transmissionpart 7 takes place, i.e., from a position according to FIG. 15 into aposition according to FIG. 21. The compression spring 44, which ispushed downwardly from the upper side by means of the counter limit stop46, pushes the transmission part 10 downwardly as the result of contactof its opposite end with the limit stop 50 of the transmission part viathe support part 48. Thus, the end face of the transmission part 10 actson the upper U leg of the clip part 68, as is also apparent inparticular from FIG. 24. Thus, at the same time, compressive force isexerted on the two lever parts 57 via the lower leg 66 so that theengagement parts 18 are pushed, against the action of the clip spring64, into their locking position. Due to the lever connection with thelever parts 56, which, accordingly, are provided twofold, the oppositelysituated engagement parts 18 are also pushed into the locking position.Thus, in this embodiment as well, the cantilever part 30, which isfixedly connected to the limit stop part 10, likewise moves verticallydownwardly. The engagement holes 51 interact with the engagementprojections 54 for directional locking.

A linear movement of the linear part 6 of the electric motor 4 in theopposite direction causes the transmission part 7 to move upwardly,thus, for example, from the position in FIG. 15 or FIG. 21 into theposition in FIG. 17 (unless only the neutral position is to be reachedfrom the position in FIG. 21). The compression spring 44 is herebycarried along upwardly by means of the head 29 and the support part 48,as a result of which the compressive stress on the support part 45increases, and by engaging against the counter limit stop 47, thesupport part pushes the activating part upwardly so that the mentionedposition can be reached.

At the same time, as can also be seen here, the cantilever part 30 andtherefore the handle 11 move upwardly together with the activating part10.

Comparable to the above-described emergency release, the emergencyrelease can also be carried out in this second embodiment.

The displaceability of the activating part 10 relative to the stationarytransmission part 7, which is basically achieved here, is explained byway of the example of the emergency release, this feature also being ofimportance independently of this example. This is carried out in eachcase against a spring force. In the second exemplary embodiment, it iscarried out against the action of the same respective compression spring44.

In both cases of emergency release, the same as in the first embodiment,a counterclockwise rotary movement of the handle 11 is required. One ofthe handle cantilevers is then supported either on the lower abutment 13or the upper abutment 12.

As can be seen from this second embodiment, the lower abutment is formedas a horizontally extending, protruding rib, which could correspondinglyalso be provided in this manner in the first embodiment. On the upperside, a detent recess is formed in the rib, in which detent recess thecorresponding part of the hand lever engages in a latching manner aftercompletion of the emergency release. Accordingly, in the case of theupper abutment 12, a receptacle is provided at the zenith of the innercurve guide, which receptacle acts in the same locking manner on thecorresponding part of the hand lever after completion of the emergencyrelease carried out in this manner.

A further embodiment of the emergency release and the actuating handleis illustrated in FIGS. 25 to 33.

In this embodiment, the actuating handle 11 is formed as a disc partwhich is rotatable about the axis of rotation d. In this embodiment theactuating handle 11 is also preferably substantially integrated into theouter contour of the housing 15, which surrounds the actuating handle inthis region. There are virtually no significantly protruding regions. Anouter surface of the actuating handle 11 preferably continues thespherical curvature of the surrounding housing region, in any case in aneutral or initial position according to FIG. 25.

In the illustrated exemplary embodiment, the actuation can in particularbe carried out by means of a fork part by engaging in the two actuationrecesses 69. In the exemplary embodiment, as can be seen, the actuationrecesses 69 are circular indentations which are formed on a diameterline on opposite sides with regard to the axis of rotation.Alternatively, a slot, for example, can also be provided which, forinstance, can be actuated with a coin.

Furthermore, as is apparent from FIG. 28, for instance, the actuatinghandle 11 in the exemplary embodiment described here, but also in allpreviously described exemplary embodiments, is disposed on the same sideas the activating part 10 with regard to an axis of rotation D of awheel 2.

The geometric axis of rotation d of the actuating handle also passesthrough the activating part 10. Moreover, in the exemplary embodimentand preferably, it is arranged to extend in a horizontal plane thatpasses through the wheel 2. In the exemplary embodiment, the horizontalplane also passes through the physical wheel axle 14 of the wheel 2.

In the course of actuating the locking device of the roller, whetherinto the directional lock according to FIG. 29 or into the total lockaccording to FIG. 30, the activating part 10 is correspondingly moved inthe vertical direction. However, in contrast the actuating handle 11 is(vertically) stationary.

In this embodiment as well (see in particular FIG. 31), the activatingpart 10 interacts with a cantilever 30, which, however, interacts hereinitially with a sliding part 70, which is guided in the housing 15 inthe direction of movement of the activating part 10. As is alsoapparent, for instance, from FIG. 28, for this purpose the cantilever 30engages in a horizontal slot 71 of the sliding part 70.

The sliding part 70 is guided in a housing insert part 72. For thispurpose, the housing insert part 72 has oppositely situated guidegrooves 73 which are open toward one another.

Guide projections 80 are formed on opposite sides at the longitudinaledges of the overall rectangularly configured sliding part 70, and areaccommodated in the guide grooves 73. The actuating handle 11 has athrough pin 74 that points in the direction facing the activating part10. The through pin 74 is arranged eccentrically with regard to the axisof rotation d of the activating handle 11. The through pin 74 actsdirectly on the sliding part 70 through the housing insert part 72.

The sliding part 70 has an upper limit stop 75 and a lower limit stop76. In the exemplary embodiment and preferably, the limit stops 75, 76are formed as transversely and horizontally extending ribs 81. In theposition corresponding to the directional lock according to FIG. 29, thethrough pin 74 is closer to the lower limit stop 76, and in the positioncorresponding to the total lock according to FIG. 30, it is closer tothe upper limit stop 75. Positions that are in each case close to or arejust touching the limit stops 75 and 76 can also occur. In any case, thedesign is preferably such that during the customary motor-drivenmovement of the activating part 10 from the neutral position into theposition of the total lock (FIG. 30) or the position of the directionallock (FIG. 29), a (rotational) movement of the actuating handle 11 doesnot yet take place. A subsequent rotation of the actuating handle 11moves the through pin 74, on a circular path, further upwardly ordownwardly so that the respective locking position is thus overridden.

FIGS. 32 and 33 each show a position after rotating the actuating handle11. Accordingly, the illustration of the detail of FIG. 32 shows thepositions of the sliding part 70 and of the through pin 74 aftercompletion of the emergency release from the position of the directionlock which was previously reached by motor drive. The enlarged detail ofFIG. 33 shows the positions of the through pin 74 and of the slidingpart 70 after completion of the emergency release from the total lockposition. In both positions, the through pin 74 is inserted in therespective detent opening 78 or 79.

Furthermore, the actuating handle 11 is biased into a neutral positionby a spring, preferably a spiral coiled spring 77. Upon actuation of theemergency release, the through pin 74 moves further into detent openings78 and 79 in the region of the upper limit stop 75 and the lower limitstop 76, respectively. The release position reached due to the emergencyrelease, which, however, preferably does not correspond to a neutralposition of the activating part, is thus fixed.

During a subsequent (repeated) motor-driven activation of the activatingpart 10, the neutral position of the actuating handle 11 and thereforeof the through pin 74 can be reached again due to the spring bias. Inthe described exemplary embodiment, this requires that the activatingpart 10 is initially moved further by motor in the direction of themovement forced on the activating part 10 in the case of an emergencyrelease and thus, in the case of the emergency release from thedirectional lock, is moved further in the direction of a total lock, andin the case of the emergency release from the total lock, is movedfurther in the direction of the directional lock.

The embodiment in FIGS. 25 to 32 is further characterized by aparticular configuration of the clip part 68 or an intermediate partbetween the activating part 10 and one or more lever parts 57, theplurality thereof being movably coupled to one another, if necessary.

The intermediate part acts on an acting part which is designed, forexample in the form of the mentioned lever part 57, which in the courseof a total lock engages with the wheel 2, preferably with an internaltoothing 17 formed on the wheel 2. For this purpose, the engagementpart, for example a lever part 57, is to be moved between an engagementposition (compare to FIG. 30, for example) and a release position(compare to FIG. 28, for example), namely, preferably to be moved bypivoting. To this end, the acting part is also mounted on the wheel 2,preferably in a pivotable manner (cf. also axle 59).

The intermediate part, the clip part 68, for example, moves theengagement part, a lever part 57, for example, into the releaseposition. The intermediate part carries the engagement part along withit into the release position during a movement of the activation part 10from the position of the total lock into a neutral position or aposition of the directional lock, the intermediate part preferablyfollowing this movement due to spring bias.

It is in particular further provided here that the intermediate part hasan activating projection 82 which is connected to the intermediate partor, more preferably, integrally formed as one piece with theintermediate part, for example, the clip part 68. This activatingprojection 82 is particularly preferably a resilient projection.Moreover, the activating projection 82 preferably provides a load on theengagement part, which preferably is formed as a lever part, at the sametime that a load is provided by the activating part 10, in which theactivating part moves back vertically upwardly, for example, therebymoving the engagement part into the release position.

Particularly preferably, a lever part 56, 57 is in each case loaded at alever extension in such a manner that during a movement resulting fromthis load, the engagement part is removed from the engagement position,so that the wheel 2 is able to rotate freely. This load is preferablyconstantly provided by the activating part. However, the load isexceeded during a movement of the activating part 10 into the positionof the total lock, since the greater force is thereby exerted on theother lever portion of the lever part 57 by means of the clip part 65 orin particular the U leg 66, and therefore the engagement part is movedby force into the engagement position. The same intermediate part, inparticular the clip part 68, thus acts twice on the same engagementpart, one action being performed with a greater force than the otherone.

With regard to a pivot axle 67 by means of which the intermediate partis pivotably secured to the wheel 2, preferably to the bottom part 20,the activating projection 82 is disposed at least partially on one sideof the pivot axle 67, and the U leg 65 is disposed on the other side,with respect to a vertical in the case of a normal position of use ofthe roller 1.

Due to the fact that, more preferably, as illustrated and described, twoengagement parts 56, 57, both being formed in a lever-like manner, aredrivingly connected to one another by means of the pivot joint 62, whichcan be formed, for example, by a pin running in a correspondingelongated hole, the described action on only one lever part 56 or 57 issufficient to also move the other one. However, in principle it wouldalso be possible, for example, to act on the one lever part 57 withregard to the movement into the engagement position and to act on theother lever part 56 with regard to the movement back into the releaseposition.

With regard to the latter, reference is made in particular to theillustration according to FIG. 34.

All features disclosed are (in themselves) pertinent to the invention.The disclosure content of the associated/accompanying priority documents(copy of the prior application) is also hereby included in full in thedisclosure of the application, including for the purpose ofincorporating features of these documents in claims of the presentapplication. The subsidiary claims in their optional subordinatedformulation characterize independent inventive refinement of the priorart, in particular to undertake divisional applications based on theseclaims.

Reference list 1 Roller 2 Wheel 3 Mounting journal 4 Electric motor 5Power connection 6 Linear part 7 Transmission part 8 Compression spring9 Compression spring 10 Activating part 11 Grip for actuating handle 12Abutment 13 Abutment 14 Axle 15 Housing 16 Antifriction bearing 17Internal toothing 18 Engagement part 19 Leg spring 20 Bottom part 21Axle 22 Axle 23 Bearing receptacle 24 Acting part 25 Lateral actingportions 26 Support part 27 Washer 28 Upper end 29 Head 30 Cantilever 31Formation 32 Projection 33 Sliding part 34 Guide 35 Positive lockingpart 36 Directional lock 37 Detent recess 38 Disc 39 Holding recess 40Locking part 41 Front end 42 Pivot part (Leg part) 43 Retaining element44 Compression spring 45 Support part 46 Counter limit stop (of 7) 47Counter limit stop (of 10) 48 Support part 49 Shank portion 50 Limitstop 51 Engagement holes 52 Step 53 Engagement projection 54 Engagementprojection 55 Flat portion 56 Lever part 57 Lever part 58 Axle 59 Axle60 Housing 61 Pivot joint 62 Pivot joint 63 Bearing 64 Clip spring 65 Uleg 66 U leg 67 Rotational axis 68 Clip part 69 Actuating recess 70Sliding part 71 Horizontal slot 72 Housing insert part 73 Guide groove74 Through pin 75 Limit stop 76 Limit stop 77 Spiral coiled spring 78Detent opening 79 Detent opening 80 Guide projection 81 Rib 82Activating projection

The invention claimed is:
 1. A roller (1), having a wheel (2) and alocking device, an activating part (10) acting on an engagement part(18) of the locking device for releasing or locking the wheel (2) aboutan axis x, and the activating part (10) being movable by a drive, amovement of a transmission part (7) between a locking position and arelease position, that is generated by said drive being transmitted onlyvia spring force to the activating part (10) for moving the activatingpart, and a spring having an underside, and the underside of the springis supported in a first support region on the transmission part, whereina second support region for the spring is formed on the activating part(10), through which second support region the transmission part (7)passes only due to compression of the spring when moved from the lockingposition to the release position or vice versa.
 2. The roller accordingto claim 1, wherein the spring (8, 9, 44) can be lifted off from thefirst support region on the transmission part (7).
 3. The rolleraccording to claim 2, wherein the spring (8, 9, 44) can be lifted offupwardly from the first support region.
 4. The roller according to claim2, wherein the first support region comprises an upper support regionfor the spring (8, 9, 44) formed on the transmission part (7) andwherein the spring (8, 9, 44) can be lifted off downwardly from theupper support region.
 5. The roller according to claim 1, wherein thespring (8, 9, 44) can be lifted off from the second support region onthe activating part (10) by means of the transmission part (7).
 6. Theroller according to claim 1, wherein the transmission part (7) isdisposed within the activating part (10).
 7. The roller according toclaim 1, wherein the roller has the two springs and that at least one ofthe two springs (8, 9, 44) is situated outside the transmission part(7).
 8. The roller according to claim 7, wherein the two springs (8, 9)are situated outside the transmission part (7).
 9. The roller accordingto claim 1, wherein the spring (8, 9, 44) can be lifted off upwardlyfrom the second support region.
 10. A roller (1), having a wheel (2) anda locking device, an activating part (10) acting on an engagement part(18) of the locking device for releasing or locking, and the activatingpart (10) being movable by a drive, a movement of a transmission part(7) that is generated by said drive being transmitted via spring forceto the activating part (10) for moving the activating part, and a spring(8, 9, 44) being supported on the transmission part, wherein a supportregion for the spring (8, 9, 44) is formed on the activating part (10),through which region the transmission part (7) passes; and wherein theactivating part (10) forms a lower central chamber which is open at thebottom and in which the spring (8, 9, 44) is accommodated.
 11. A roller(1), having a wheel (2) and a locking device, an activating part (10)acting on an engagement part (18) of the locking device for releasing orlocking, and the activating part (10) being movable by a drive, amovement of a transmission part (7) that is generated by said drivebeing transmitted via spring force to the activating part (10) formoving the activating part, and a spring (8, 9, 44) being supported onthe transmission part, wherein a support region for the spring (8, 9,44) is formed on the activating part (10), through which region thetransmission part (7) passes; and wherein the activating part (10) actson the engagement part by means of an intermediate part acting as aspring, wherein the intermediate part is pivotably mounted in the wheelfor movement between an engagement position and a release position. 12.The roller according to claim 11, wherein the intermediate part movesthe engagement part into the release position.
 13. A roller (1), havinga wheel (2) and a locking device, an activating part (10) acting on anengagement part (18) of the locking device for releasing or locking thewheel (2) about an axis x, and the activating part (10) being movable bya drive, a movement of a transmission part (7) that is generated by saiddrive being transmitted via spring force to the activating part (10) formoving the activating part, and a spring (8, 9, 44) having an underside,and the underside of the spring is supported on the transmission part,wherein a support region for the spring (8, 9, 44) is formed on theactivating part (10), through which region the transmission part (7)passes when moved from a locking position to a release position or viceversa; wherein for carrying out an emergency release, the activatingpart (10) is actuated by means of a handle (11) acting on the activatingpart, which handle is accessible from the outside.
 14. The rolleraccording to claim 13, wherein the handle (11) moves together with theactivating part (10).
 15. The roller according to claim 13, wherein thehandle (11) is fixedly connected to the activating part (10).
 16. Theroller according to claim 13, wherein the activating part (10) can bemoved relative to the stationary transmission part (7) by means of thehandle (11).
 17. The roller according to claim 16, wherein the movementof the activating part (10) takes place relative to the stationarytransmission part (7) while carrying along the support region for thespring (8, 9, 44).
 18. The roller according to claim 13, wherein thehandle (11) can be moved relative to a stationary abutment (12, 13)within the roller.
 19. A roller (1), having a wheel (2) and a lockingdevice, an activating part (10) acting on an engagement part (18) of thelocking device for releasing or locking the wheel (2) about an axis x,and the activating part (10) being movable by a drive, a movement of atransmission part (7) that is generated by said drive being transmittedvia spring force to the activating part (10) for moving the activatingpart, and a spring (8, 9, 44) being supported on the transmission part,wherein a support region for the spring (8, 9, 44) is formed on theactivating part (10), through which region the transmission part (7)passes when moved from a locking position to a release position or viceversa; and wherein the spring comprises only one spring (8, 9, 44)between the transmission part (7) and the activating part (10).
 20. Theroller according to claim 19, wherein the only one spring is supportedon the transmission part (7) and the activating part (10).